South Dakota Public Utilities Commission

Address

State Capitol, 500 East Capitol Avenue, Pierre, SD 57501-5070

Phone

(605) 773-3201

Website

puc.sd.gov ↗

Utility landscape

• NorthWestern Energy IOU

  Western and central South Dakota, including Rapid City area and Black Hills region

  NorthWestern acquired the South Dakota electric and natural gas assets from Montana-Dakota Utilities and has been active before the SDPUC on rate cases and infrastructure investment cost recovery. The commission has scrutinized capital cost allocations between Montana and South Dakota jurisdictions.

• Xcel Energy (Black Hills Power predecessor assets now under NorthWestern; Xcel serves northeastern SD) IOU

  Northeastern South Dakota electric service in limited areas bordering Minnesota

  Xcel Energy's Northern States Power subsidiary serves a small footprint in northeastern South Dakota and coordinates multi-state rate filings that require SDPUC review for South Dakota-allocated costs.

• Montana-Dakota Utilities (MDU) IOU

  Natural gas distribution in portions of western and central South Dakota

  MDU retains natural gas distribution service in parts of South Dakota following asset restructuring and has pursued infrastructure cost recovery riders before the SDPUC for pipeline replacement programs under federal integrity mandates.

• East River Electric Power Cooperative coop

  Eastern South Dakota, wholesale power supplier to numerous distribution cooperatives

  As a generation and transmission cooperative, East River's wholesale rate changes flow through to retail cooperative members and are monitored by the SDPUC for downstream retail rate impacts; renewable energy procurement and transmission expansion are active policy areas.

• West Central Electric Cooperative coop

  West-central South Dakota distribution territory including portions of Lyman, Jones, and surrounding counties

  West Central has engaged with the SDPUC on rural grid reliability and cost-of-service matters; ongoing participation in regional transmission planning under Western Area Power Administration coordination affects rate structures.

• Sioux Falls (City of Sioux Falls Utilities) muni

  Electric and water service within Sioux Falls city limits and adjacent service area

  Sioux Falls operates its electric system largely outside SDPUC retail rate jurisdiction but coordinates on certificated territory boundaries and has been expanding renewable procurement commitments aligned with city sustainability goals.

Key issues

• NorthWestern Energy general rate case for South Dakota electric and gas operations: following significant capital investment in transmission infrastructure and grid modernization, a rate filing is anticipated or pending before the SDPUC that will test cost-of-service methodologies and authorized return on equity in a rising interest rate environment.
• Renewable energy integration and transmission cost allocation: South Dakota's substantial wind generation capacity has intensified debates at the SDPUC over how interconnection upgrade costs and new transmission lines serving wind exports are allocated between in-state ratepayers and out-of-state beneficiaries, particularly in the context of MISO Tranche 2 projects.
• Broadband infrastructure certification and pole attachment: the SDPUC has active proceedings on pole attachment rates and conditions as rural electric cooperatives and ISPs seek to deploy broadband over utility infrastructure under the state's rural broadband expansion initiative, raising cost recovery and non-discrimination issues.
• Carbon pipeline siting and eminent domain authority: proposed CO2 capture and sequestration pipelines crossing South Dakota have generated contested siting proceedings before the SDPUC, with significant landowner opposition and unresolved questions about whether the commission's pipeline siting authority extends to granting condemnation rights to private CO2 pipeline developers.
• Natural gas infrastructure replacement and safety cost recovery: MDU and other gas distributors are seeking approval of pipeline replacement cost trackers tied to federal Distribution Integrity Management Program requirements, with the SDPUC examining the appropriate rate of recovery and whether tracker mechanisms bypass traditional rate case scrutiny.

Upcoming

• 2026-09-15

  Estimated deadline for initial comments in NorthWestern Energy South Dakota rate case procedural schedule; parties including SDPUC staff and intervening industrial customers expected to file testimony on cost allocation and rate design.

• 2026-10-07

  Estimated SDPUC open meeting at which commissioners are anticipated to take up CO2 pipeline siting application status and address outstanding questions on eminent domain authority and landowner notification compliance.

• 2026-11-18

  Estimated evidentiary hearing date for contested pole attachment proceeding involving East River Electric Power Cooperative and rural broadband provider seeking standardized attachment rates and non-discriminatory access terms.

• 2027-01-12

  Estimated date for SDPUC final order in NorthWestern Energy South Dakota rate case, contingent on hearing schedule; outcome will set precedent for infrastructure cost recovery mechanisms and ROE benchmark for future IOU filings in the state.